A potential distribution map of wintering Swan Goose (Anser cygnoides) in the middle and lower Yangtze River floodplain, China

Abstract

Background: Reliable information on the distribution of target species and influencing environmental factors is essential for effective conservation management. However, ecologists have often derived data from costly field surveys. The Swan Goose (Anser cygnoides), a vulnerable Anatidae species, winters almost exclusively in China's Yangtze River floodplain, but wintering numbers have been steadily decreasing. To better safeguard this unique species, modern modeling approaches can be used to quantify and predict its suitable wintering habitat. Specifically, a potential wintering distribution map of this species is critically important.Methods: This study used the maximum entropy approach to model a distribution map of this species. In total, data from 97 up-to-date sites were extracted from 1263 survey sites (excluding duplicate data). After eliminating spatial autocorrelation, 11 environmental variables, including factors related to climate, land structure, vegetation, and anthropogenic activities, were used for model prediction. Results:The prediction distribution map shows that the population has concentrated mainly in the boundary area of Anhui, Hubei, and Jiangxi provinces, especially along the Yangtze River. Modeling results suggest that areas within the middle and lower Yangtze River floodplain, such as those in Hunan and Hubei provinces and the eastern coastal area of Zhejiang Province, demonstrate a potential level of "medium" suitability for this species to winter. Conclusions:Results from this study provide fundamental information for the restoration and management of the Swan Goose. Our "visualized" potential distribution map can assist in planning optimal conservation strategies, and consequently may help to increase the number of wintering populations in China.

Shrinking Habitats and Native Species Loss Under Climate Change: A Multifactorial Risk Assessment of China's Inland Wetlands

“…Overall, we identified that climate plays a major role in regulating species suitability in wetlands. In particular, isothermality, representing the evenness of temperature relative to annual oscillations, was identified as the most important factor, which is consistent with previous findings (An et al., 2018; Garris et al., 2015). Isothermality influences the water supply of wetlands via its substantial impacts on seasonal hydrologic cycling, especially for wetlands reliant on the runoff from spring melt as their primary water source.…”

Organising a juvenile ratio monitoring programme for 10 key waterbird species in the Yangtze River floodplain: analysis and proposals

“…This latter feature is important because the species considered here all differ in their diet and habitat use. For example, the Swan Goose forages for submerged tubers (An et al 2018(An et al , 2019, Bean Goose grazes the above ground parts of Carex, as well as consuming grain seeds and plant buds (Yang et al 2016), while the family Gruidae can prey on fish, crustaceans, invertebrates and other animals (BirdLife International 2017).…”

Seasonal and regional differences in migration patterns and conservation status of Swan Geese (Anser cygnoides) in the East Asian Flyway

“…The Swan Geese (Anser cygnoides) is an endemic East Asian species listed by IUCN as Vulnerable, which now breeds mainly in Mongolia and adjacent areas of Russia and China and migrates to winter almost exclusively in China (Batbayar et al 2011;An et al 2018;Damba et al 2020). The species has shown long-term major contractions of breeding and wintering range as well as recent continued declines in abundance (Fox and Leafloor 2018;Damba et al 2020).…”